The use of the technetium-99m labeled phosphorus containing complexes for skeletal imaging has been shown to offer several advantages over the strontium isotopes and fluorine-18. In order to make optimum use of these radiopharmaceuticals for diagnostic procedures a study has been designed to obtain the uptake and clearance characteristics of Sr85, F18, and mTc99 labeled polyphosphate, prophosphate, and diphosphonate. These determinations will first be carried out in the rat, using a single healing fractured tibia as a model for bone undergoing rapid remodeling. Serial short-term studies will be made to assay activity levels in bone, muscle, soft-tissue, blood and healing fractured bone. Those radiopharmaceuticals showing greatest diagnostic potential in terms of good uptake in the skeleton, high abnormal-to-normal bone differential, and rapid soft-tissue and blood clearance, will also be evaluated in patients. Both analog and computer-processed serial image data in addition to serial blood and urine assays will be obtained in selected patients for these radiopharmaceuticals. The results obtained in this study will be used to document comparative usefulness of the different radiopharmaceuticals for bone imaging, providing data for optimum imaging times, comparative uptake and distribution characteristics, comparative merits of camera and rectilinear scanner images and dosimetry based on patient kinetics.